Surface plasmon enhancement of broadband photoluminescence emission from graphene oxide.

The photoluminescence (PL) emission studies of both graphene oxide (GO) and partially reduced graphene oxide (rGO) have been investigated. It has been observed that GO has broadband emission from the green to near infrared range and upon reduction rGO shows blue PL emission. The broadband PL emission is due to the recombination of the electron-hole pair in the sp(2) domain embedded within the sp(3) matrix. The broadband PL emission also suggests the existence of various sizes of the sp(2) domain within the same matrix. Furthermore, PL emission from GO in the presence of an Au metal thin film has been investigated. It has been observed that the entire broadband emission from GO in the green to near infrared wavelength region is enhanced significantly at room temperature. The Au-GO interface exhibits surface plasmon resonance in the visible wavelength region and is responsible for over 10 fold enhancement in the photoluminescence at ∼2.36 eV. The electrical property measurements on the GO and rGO thin films suggested that the rGO exhibits significantly higher electrical conductivity compared to that of the GO thin film. Furthermore, the GO thin film exhibits semiconducting behaviour. These properties make the material quite suitable for fabrication of new generation photonic devices.